1、3280.8ft Wireless Distance: Wireless voice intercom bell wireless distance of about 3280.8ft (no obstruction), no network, no wiring, power on that use. 2、USB Charging: Mobile call doorbell uses a special intelligent intercom chip with strong penetration, USB charging, convenient for your use. 3、IP54 Waterproof: Wireless call doorbell surfaces high gloss UV process, outdoor doorbell IP54 waterproof, can resist the harsh environment. 4、Humanized Design: Intelligent humanized design, with intercom light and power light display, the user can see at a glance. 5、ABS Material: Home wireless doorbell is made of ABS material, wear resistant and durable, can be used for a long time. Item Type: Voice Intercom Doorbell Material: ABS Weight: Approx. 304g / 10.7oz Battery: 2 x Li Polymer 2000mAh (Included) Working Temperature: -20℃ to 55℃ Wireless Distance: Approx. 1000m / 3280.8ft (Without Obstacle) , Approx. 20m-50m / 65.6-164.0ft (Without Obstacle) Wireless Frequency: Approx. 410m-490m / 1345.1-1607.6ft Working Time: Outdoor Doorbell > 6 Months, Indoor Doorbell About 1 Week Waterproof Level: Outdoor Doorbell IP54 Outdoor Doorbell Size: Approx. 18 x 61.6 x 121mm / 0.7 x 2.4 x 4.8in Indoor Doorbell Size: Approx. 18 x 116 x 56 x 70mm / 0.7 x 4.6 x 2.2 x 2.8in 1 x Indoor Unit (Ship with Inbuilt Battery) 1 x Outdoor Unit 2 x Power Cord 1 x Screwdriver 1 x Base 1 x User Manual